What do Peter Kay, Victoria Beckham, Gordon Ramsay, Chris Moyles, Terry Wogan, Kerry Katona and Steven Gerrard have in common? They were all in last week's Sunday Times bestellers list. The only good thing about this is they helped to keep other memoirs from the likes of David Blunkett, Wayne Rooney, Ashley Cole, Jordan, Jade Goody, Pete from Big Brother, Gary Barlow and Janet Street-Porter out of the list.

In the course of the last year, most of these books have crossed my desk at some point and they really are as dull as you might imagine. Some are better written than others, but that's beside the point. It's the predictability that kills you. The loving childhood, the touch of self-deprecation, the leaden self-promotion, the daringly un-PC asides, the clunk of name-dropping, the soporific anecdotes that have been signed off by the agent and the trivial self-disclosure.

These books are writing by numbers. The trouble is that publishers are finding it increasingly hard to make the numbers stack up. Having reportedly paid around £400,000 for the Blunkett memoirs, Bloomsbury can't be happy with current sales of little more than 1,000 copies. Hodder Headline won't be best pleased with a return of about 4,000 sales after paying Ashley Cole an estimated £250,000, and Harper Collins must be facing a huge loss on its £4m four-book investment in Wayne Rooney, with sales to date of just 35,000.

What is going on? The obvious answer is that celebrity is being rapidly devalued. Assuming that anyone halfway interesting has already written their memoirs, publishers are left with the choice of either going back to the usual suspects for sloppy seconds or signing up the desperate and the dull. Naturally they do both. Board that bandwagon, get the books into the shops in their thousands and worry about the returns in next year's accounts.

It's not all quite as mindless as it seems. Some celeb memoirs sell much better than expected. Both Pamela Stephenson's hagiography of her husband, Billy Connolly, and Sheila Hancock's lessons in stoicism took even their publishers by surprise. So there is a market there. But as no one has a clue which one will turn out to bankroll the rest, there's an understandable tendency to back plenty of horses. The trick is to spend as little as possible in the process; the first instalment of Jordan's autobiography was bought for £10,000 and sold in the hundreds of thousands. But bargains such as this have become increasingly rare, so publishers have come to depend on Plan B - selling the serialisation. Who cares if you've paid £200,000 for a book that only sells a few thousand copies if you've recouped most of your cash from a newspaper?

The real losers in all this are the readers. And not just because they already know everything of any interest before they get to page one. When a publisher hands over a large advance, it earmarks a proportionate amount of its marketing budget to selling the book. Celebs are the ones who are going to end up on chatshows and their memoirs will dominate bookshop displays, crowding out other authors.

This Christmas, most people will play as safe as the bookshop buyers and walk out with a Jeremy Clarkson or a Gordon Ramsay, happy in the knowledge it won't be them who has to read it. Chocolate used to be marketed on the myth that buying someone a box was a sign that you loved and cared for them. In reality, it showed that you didn't - or not enough to buy them something that requires thought. Celebrity memoirs seem to be working to the same principle.

· John Crace's second volume of The Digested Read has just been published.